. >>> and the world's longest high-speed rail line is now open for business in china. the first trip was this morning as passengers boarded a train in bay bridge. the line is 1,428 miles long ending in the southern city of [ non-english language ] the city takes 8 hours compared with the more than 20 hours for the previous system >>> some encouraging news on child obesity. the problem appears to be easing among small children in poor families. the centers for disease control followed 27 million children between the ages of 2 and 4 from 1998 to 2010 and the rate of obesity decreased from 15 to in3 to 14.9%. extreme obesity went down by 2%. >>> a new study suggests there may be a genetic component to how children feel pain. researchers at geneva university in switzerland analyzed the dna of 168 kids recovering from major surgery. well, the young patients with a certain gene variant felt more pain. >>> a warning this morning about a popular cosmetic medicine. the food and drug administration is warning hundreds of medical practices that botox they have could be bad. cbs r